This callback is used to get the current value of the period in which Smack does bundle and defer
outgoing stanzas.
Smack will bundle and defer stanzas if the connection is authenticated
and if a bundle and defer callback is set, either via
XMPPTCPConnection#setDefaultBundleAndDeferCallback(BundleAndDeferCallback) or
XMPPTCPConnection#setBundleandDeferCallback(BundleAndDeferCallback), and
#getBundleAndDeferMillis(BundleAndDefer) returns a positive value. In a mobile environment, bundling
and deferring outgoing stanzas may reduce battery consumption. It heavily depends on the
environment, but recommend values for the bundle and defer period range from 20-60 seconds. But
keep in mind that longer periods decrease the realtime aspect of Smack.
Smack will invoke the callback when it needs to know the length of the bundle and defer period.
If
#getBundleAndDeferMillis(BundleAndDefer) returns 0 or a negative value, then the
stanzas will send immediately. You can also prematurely abort the bundling of stanzas by calling
BundleAndDefer#stopCurrentBundleAndDefer().